Apparatus for trimming grid electrodes



Jan. 19, 1937. H. P. KRONENWETTER ET AI. 2063523 APPARATUS FOR TRIMMINGGRIDELECTRODES Filed June 12, l935- III Q ililiill INVENTOR S ""'TORNEYPatented Jan. 19, 1937 PATENT OFFICE APPARATUS FOR TRIMMING nuzcxmonrcsHarold P. Kronenwettel' and Ea.rl E. Moore, Emporium, Pa. assig'n0l's toHyxrade Sylvania.

Corporation, Salem, Mass.

Massachusetts a corporation n! Applibation Junel2, 1935, Serial N0.26,235

11 Olaims.

electrodes, as examples of such machine s may be mentioned theseillustrated in Patent N0. 15 1814'770 and Patent N0. 1897460.

It has been the customary practice heretofore in winding grids incontinuous grid-strips to' fasten the individual turns or lateral wlresto the grid side-rod or side-rods by a welding, peen-' 20 ing or swagingoperation, and to leave one or more turns unfastened so that the gridstrip may be cut into unit lengths with the side-rods extending beyondthe lateral wires. 'prior machines thisresults in the leaving 01' a5'considerab1e 1oose length cf the cut end of the lateral wire, a.nd hasnecessitated. the services of an operative who manually trims the 1ooseunfastened ends, but in order to facilitate thi manuell trimmingoperation it has been found 30 necessary to leave more than one gridturn unv fastened so that the operative may have sufficient length ofwire to grasp during the trimming operation. Where a large number ofgrids are be1ng manufactured these trimmed turns- 35 become wasteproducts and add appreciably to the cost of the flnished'tube'intowhichthe grid is incoiporated. Apart from the increased cost is the fastthat with the ordlnary manuizl method of trimmixig these 'loosegrid-ends, the manual contact with the gr1d W1res results in an"uniawoidable percent f contamination of the grld surface whichcontamination may cause wlde 'diverg6ricesbetweri the chara.cteristics01 the tubes into which the grids are assembled. 4 Accordirxgly it-isanother object of this Invention to provide a device which automatioallytrims the loose en ds'of wire-wound grid electrodes s as to reduce to amlnimum the percent of Waste wire and to avoid the contamir nation andother undesirable efiects incldenta.l to the handling of the gridsduring the manual trimming operation.

'A.feature of the invention relates to a device 55 whereby the 1ooseends of a, grid electrode wire In these may be accurately trimmedwlthout affecting the usual grid side-rod.

Another fea.ture relates to a method 01 fusing the 1oose ends of awire-woui1d grid.

A further fea.ture relates to an automatic de- 5 vice for trimming theloose ends of a. wirewound grid, which device may be rea.dily applled toa so-called continuous grid-strip wlnding machine.

A still further feature relates to the novel organization, arrangementa.nd relative location of parts which go to make up an efliclent andaccurate grid-electrode trimmi ng device.

Other features and advantages not specifleally enumerated will beapparent fter a consideration of the following descrlptions and theappended claims.

While the invention will be described herein as applied 139 certainwellknown typ s of grid winding machines, it will be understood thatthis 1s done merely for explanatory purposes and notby way of limitationand furthermore since these grid-windlng machines are wellknown in theart the drawing herein represents the mechanism of such machines indiagrammatlc form o nl y. In the drawing,

Fig. 1 shows in diagrammatic plane view the invention as applled to a,continuous grid-strip winding machine. Y

Fig. 2 is a diagrammatic elevatlonal view oI part of the mechanism-ofFig. 1.

Fig. 3 is a. diagrammatic end view of the mechanism shown in Figs. 1 and2.

F 'ig.- 4 is an enlarged view of part cf 'a. grldstrip showing thepoints at whlch the uniastened turn of the grld wire 1s cut accordlng tqthe invention. 1 J L Fig. 5 shows a. aectlon 0Lgrid-strip wound in oneknown manner.

Rei'erring to'the dra.wing the numeral I rep- 40 resents a.suitable'base up0n which are supported wlre turns, and suitablemechanlsm is 'provided to peen, or swage the notched slde-rod so as tohold the turns of the flne wire firmly in place i n the said notches.When the requisite number of turns have been wound the Ieeding mechanismmay advance the side-rods so as to increase the pitch of the next turnas indlcated in Fig. 5. The purpose of this skip4urn is to provide theoperative with a suflicient length of Ioose wire so tha.t the gridsection may be handied and trimmed by band. In another type o! gridWind- Ing machine instead of producing the skip-turn for this purpose,the grld is wound with uniform pitch except that at regular intervalsone o1 more turns a.re left unfastened. With this lai;ter type ofmachine, in order that the loose ends may be trimmed it is necessary forthe operative to unwind the unfastened turns prlor to trimming the same.In accordance with the present lnventlon elther met h0d of winding maybe employed, prei- 'erably however the mechanism 2 Is arranged to windthe flne wire 5 with uniform pitch as shown in Fig. 2 and at regularintervals the pe.ening or swagmg is omitted-from a single turn as indi--cated by the numeral 8 in Fig. 4 and by suitable mechanism about to bedescrlbed the flne wire 5 is electrically cut at the points marked bythe arrows. For this purpose the wound grid-strip 1s fed pa.st a pointedelectrode 1 which Is Insulatingly1supporte'd onan arm 8 plvoted a1: thepoint 9 on a bra.cket III attached to base I, it being understood thatthe arbor in machine 2 which carries the side rods 3 anti 4 is rotatedIn the direction of the arrow (Fix. 3) at the same time that the gxidstrip is being fed Iorwa.rdly Irom the ma'chine as indIcated. Arm II isprovided with an extension II in which Is adjustably mounted the tensionadjusting screw II which Is adapted to bear against a. stop II fastenedto a support I5 rigidly mounte d on base I. A tension spring I6 has oneend Ifastened to support I5 a.nd the ot-her end to arm II thus impellingthe electrode I toward the grId-strip. 'I'he spe.cing between thepointed end ot electrode 'I und the grid-strip may be accuratelyregulated by the ad.- Justing screw I2. Preferably the electrode I is somounted that when moved I;o cutting position II; is in registry with thepart of the grid-strip marked by the arrows (Flg. 4) and when eurrentnasses, the lateral grid wire Is cut by a fusing operation as close aspossible I:o the slde- IOd 3 but without this latter rod. In thiscounection II; should be noted tha.t the electrode I is so polnbed andis moved a.t such an angle tha.t lt flrstfuses the loose gricl tum atthe polnt A in Iront of the side-rod 3 und subsequently tuses this turnat the point B in back o! the side-rod I.

In order that the electrode I may be operated in proper timed relationwith respect; to the rate at which the grid-strip 'is -ted I romthewindin8 maohine 2, there is provided a cum II amxed to a shai't IIIwhich may be driven In the proper timed relation Irom the main shattfl!which drives the winding machine 2, lt being anderstood thal:appropriate gea.ring a.n d bea.ring brackets are provid ed Ior shaft I8aa Indicated by mmierals III, 2I. Afllxed t o base I is a pI-vot pin 23on which Is mounted the pivoI; block 24 for vertical rotation about saldpin 23. Passing through block 24 is an arm 25 which ha.s fastened to oneend the cum follower 26 adapted to ride on cam II. The opposite end ofarm 25 is Connected by a link 21 bo the electrode support arm II. Aswill be seen the cum II is provided with two Iow sectors 28, 2,9, sothat when the 1'ollower 2 is In these sectors'the electrdde I isadvanced to cutting position a.s indicated by the arrows in Fig.

4. 'I'he speed o1 rota tion of cam II Is related so the speed o1 feedingof the grid-strip so that when the follower is in sector '28, theelecirode I is in alignment with the point A o! the unfastened gridwirre tum (see FIg. 4) and when the outting position is so timed'withthe Ieedinm movement of the gricI-strip that the unfastened turn of thefine grid wire alone is out und during the remainder of the i'eedingmovement the electrode I is mit of cutting relation with the gridstrip.It will also be understood ahoi; sinne the gricI-strip is wound so thatsuccessive unit;

lengths thereof have the grid wires Iastened, the

cam II maintains the electrode I out 01 cutting relation so long as thefastened turns are passing the cutting electrode. If desired a. pair ofoutting knives or rollers indicated by the numerals 3II, 3 I, may bemounted in such a. way thai:

as the trimmed unit lengths of the grid-strip are fed pasi; thesecutters the side-rocls 3 and 4 a.re cut at the points C, D, thusproducing finished wound grids of unit length with the flne gridwiresacourately trimmed and with suflicient 1ength of sic ierods 3, I, left;to serve as attach- 1 ment Iugs or supports for the grid. In I;hiscouneotion II: will be understood of cdurse that the winding unit 2 maybe so arranged that two or more turns of the grid wire are lefI:unfastened.

und the cam II may be correspondingiy designed 1 to trim only theseloose turns, thus allowing a greater length of exposed side-rod Ior gridsupporting purposes. It will also be obvlous that instead o! employingonly one cuttlng electrode, a pa.ir of aligned cuttsing electrodes maybe employed so that the grid-wire may be trimmed adjacent both siderods. Thus in connection with the type of grid-strip shown in Fig. 5where all the grid turns a.re fasteiied to thesIde-rods 3, 4, a Set of'three cutting electrodes slmilar to electrode I ma.y be insulatinglymounted on the arm 8 so that one electrode cuts the grld wire a.t

point E, the second electrode a.t point F, and the third electrode atpoint G thus completely trimming the skip-turn" between adjaceni; unitlengths o! the grId-strip.

' In accordance with the present Invention it is preferred to aflfectthe trimming o! the ioose grid turns by electrical means. Thus as shownIn Fix. 1 the{electrode I Is connected by a. conductor 32 to oneterminal of a suitable souroe o1 current .l3,

the opposite terminal of which is connected I:o the base I und thenceoonduotively through the various parts described above, to thegrid-strlp.

- Consequently when the electrode I is moved into cutting positlon a.sdescribed, the flow-of eurren t at the point o1 contact with the gridwire causes a fusi ot1 o! the Iatter resulting in a, clean cut andwithout bur'ning or afl'ectlng the adjacent side-rod. Ifdesired thedevices III a.nd II which are employed to cut the sl de-rocls may bereplaced by electrodes similar I:o 'electrode 1 to afl'ect the outtingof the sIde-rods electrically. In this case of cou.rsethe side-rodcutting electrodes will be moved into and out o1 cutting engagemeni:with the sIde-rods, by mechanism simi- Iar to that for moving electrodeI.

In certain types o1 grids having relatively coarse wires or mesh, it maybe impractical to move the pointed electrode I so that lt fuses theloose turn in back of the slde-rod as descrlbecl in connection wlth thefusing of the turn at the point B. In thls case two separate fuslngelectrodes may be employed. Thus as lndlcated schematl'cally in Flg. 6,arm 8 whlch carrles the electrode 1 is linked' to another arm 35 whichls pivotally mounted at 36 so that when the arm 8 is operated by wiseoperated. Arm 35 will then carry a polnted electrode 31 simllar toelectrode 1 but displaced the distance of one turn.- Wlth thlsarrangement therefore. a single cam such as the cam I1 mta.y operate themechanism so that electrode 1 fuses the loose grid tum (Flg. 4) at thepoint A in freut of the slde-rod 3 whlle slmultaneously therewlth. thepolnted electrode 31 fuses the loose turn at. the point B in back of theslde rod. If desired the electrodes 31 and 1 may be adjustably mountedin thelr holders so as to accommo date the mechanlsm to difierent pltchgrlds. It will also be obvious that lnstead of employlng a single cam'to operate the electrodes 1 and 31. two separate cams may be employed sothat the said electrodes 1 and 31 niay be operate'd independently in anydesired tlmed relation wlth respect to each ot.her.

Various 'changes and modiflcatlons may be made herein without departlngfrom the spirlt and scopei ot the inventlon.

What ls claimed is:

1. In a machine for trlmming cage-like grld electrodes of the typehavlng a metal slde-rod and a fine wire wound therearound, a wlresevering eleetrode, means to feed a wound grld-strlp past said electrodeand. to rotate sald grld strlp in front of said electrode me'ans formovlng sald electrode into severlng relatlon with sald grldstrip, andmeans for operatlng said severing means and said feedlng and rotatlngmeans in timed relat ion to each other.

2. In comblnatlon, a grld wlndin'g and feeding unit including means torotate sald grld aboutits longitudinal axls, a grld wlre trimmlng unlt,

an electrode for severing the wound grld wlre at predetermlned spacedlntervals' and means. for oscillating said electrode into and out ofsevering relation with the grld wlre in tlmed relations to the saldfeeding and rotating means.

3. In a devlce of the charaeter descrlbed a grid-strl p feeding unitlncludlng means to rotate said grid about its longitudinal axis, a grldwlre trimming unlt, an electrode for severing a grld wire adjacent ltssupport rod. a tlmlng cam for controllingthe operation of said severingmeans and means for operatlng said cam in tlmed. relation to theoperation of sald feecllng and rotating means.

4. In a machine for trimmlng cage-llke grid elect rodes of the typecomprislng a metal siclerod and a fine wire hellcally wound around andfastened to thesiderod, the comblnatlon of a severing electrode,xr'1eans to feed. the grid wlth its side-rod and flne*wlre past saidelectrode said severing electrode belng normally dlsposed away from saidfine wire, and means to move sald electrode toward the fine w ire but atan angle tc the side-rod to sever the fine wire adjacent the side-rodand without afieetlng sald slde-rod.

5. In a machlne for trimmlng cage-llke grld electrodes f the typecornprislng a metal slde-rod and a fine wire helically wound around andfastened to the side-rod, the comblnatlon of a pointed cuttingelectrode, means to feed a. grld with the slde-rod and fine wlre pastsald cutting the llnk 21 the arm 35 ls l1ke.

electrode, a source of current havlng one termlnal connected to the grldand the other terminal connected to said electrode, and means to movesald electrode toward the fine wlre to strike an arc between the polntedend of the electrode and the fine wlre only.

6. In a machlne for trimmlng cage-like grid electrodes of the typecomprising a metal siderod and a fine wlre helically wound and fastened1:0 sald. slde-rod, the comblnation of a trimming electrode means torotate the grid around its longitudinal axis and to feed the grldlongitudinally past the tri mming electrode, sald grld having at leastone turn of the fine wire unfastened, means to move the trlmmingeleetrode toward said fine wlre, the last-mentioned means beinautomatlcally operated in timed relation to sald f eecllng androtatlngmeans so that the trimming .electrode flrst trlms the end of theunfastened turn in tront ot the side-rod and then trims the end cf theunfastened turn on the rear of the side-rod.

' '1. In a. machlne for trimmlng cage-llke grld electrodes of the typecomprislng a metal slde-rod arxd a fine wlre helically wound around andfastened to the side-rod; the combinatlon of a pointed trlmmlngelectrode, means for formlng and f6edlng a grld strlp past sald trimmingelec- 'trode said strip havlng at least one turn unfastened to thesicle-rod, means for movlng said trimm1ng electro'de lnto and out of arcformlng relatlon with one end of sald unfastened turn means to rotatethe grld strlp to bring the other end of said unfasten ed turn into amforming relatlon with sald trlmming electrode, and means fqr malntalnlng'sald electrode away from said 'grid strip when the latter ls rotating8. In a machine of the character described, the comblnation cf a unitfor winding and feeding longitudlnally a cage-llke grld in the form of afine wire hellcally wound around a metal side-rod, a unlt for severlngthe fine wire at predetermined intervals lncludlng a pointedarc-producing electrode, and means f or automatically operating bothsaldu'nlts in timed relation so that one side of the grid strip is firstpresented to said pointed elec trode, andthen the other side of the grldstrlp is presented to salrl polnted electrode.

' 9. In a machlne for trimmlng cage-like grid electrodes of the typecom'prising a rigid metal side-rod and a plurality of fine lateral wiresbent\ around. sald slde-rod, a palr of polnted electrodes,

means for fee;ding a grld strlp past sald electrodegs, one of saldelectrodes being dlsposed With lts polnt adjacent the lateral wlres onone side of the grld strip, and the other of said electrodes beingdisposed with its point adjanent the lateral wiresmn the other side oithe grid strip, and means for moving sald pointed electrodes lnto andout; of arc-procluclng relatlon with sald lateral wires in tlmedrelation to the ieeding movement ofthe grid strlp so that said pointedelectrodesx strlke an arc to said lateral wlres closely adjacerlt the side-rocl but without afiectlng said side-rod.

10. A machine according to claim 9 in which certaln of the lateral wlresare fastened 190 the side-rod and other lateral wires are unfastened,and the movement oi the pointed electro des ls timed so that an arc isproduced only when the ends of the unfastened lateral wires are inreglstry with the said pointed electrodes. A

. 11. In a machinefor manui'acturing radio tube electrodes ofthecage-llke type, me'ans for windlng a fine wire around a pair of metalside-rods wlth some cf the turns fastened to the side-rocls and otherturns unfastened, means for severlng the unfa.stened turns comprislng apointed arcproducing electr'ode, a member in which said. electrode isadjusta.bly mounted, a cam for uperating seid member, and. means foroperating said cam in timed r elation'to the windi ng of sa.id fineW1're so that saicl pointed electrode is moved to severing position onlywhen the ends of the unfastened turns are in registry therewith.

